One advantage of digital cameras over digital film based cameras is that digital cameras have the ability to store data along with a captured image that may later be accessed by a viewer. For example, once the digital image has been transferred from the digital camera to a PC and displayed, a user may also view information about the image, such as date and time of capture, the name of the image, and image size, for instance. Typically, the data regarding a captured image is stored in metadata within the image file of the captured image.
A conventional image file typically includes a header, image data itself, and the metadata. The image file may optionally include a thumbnail image and/or a reference to audio data. The header preferably includes information that identifies and describes the various contents of image file. The image data contains actual captured image data, the resolution of which depends on the settings of the image capture device (e.g., camera, scanner, and the like). The image metadata stores various types of data that correspond and relate to the image data. The image metadata may be populated by the image capture device at the time of image capture, or subsequent to image capture by a user when cataloging the images.
The image metadata may comprise system metadata and user metadata. System metadata is typically populated by the image capture device and includes various types of camera information that preserve command settings at the moment of capture and correlate with the captured image data. For example, system metadata may indicate focus setting, aperture setting, and other relevant information that may be used for effectively processing or analyzing the corresponding image data. The data written to the system metadata is controlled by the camera or scanner and cannot be modified by the user.
The user metadata, in contrast, enables the storage of data that the user enters on either a PC or on the image capture device. For example, most, if not all, images depict a scene that includes multiple objects (e.g., people, buildings, landmarks, nature, etc.). The user may wish to identify these objects by entering metadata describing the objects. Image applications exist that enable the user to do so by entering this information in text format. The text is then stored as user metadata and associated with the image. When the image is subsequently displayed using the same or a different image application, the metadata associated with the image is made available to the viewer. For example, the metadata may be displayed and/or printed as text along with the image.
Although the conventional metadata allows the user to more fully describe the objects appearing in the image, there are limitations to the metadata. For instance, the metadata may not adequately describe the image. In particular, if the metadata describes more than one object depicted in an image, the user often has a difficult time determining which descriptions pertain to which object. For example, assume an image depicts two people and two houses, and the metadata identifies the individual's names (e.g., Richard and Scott), as well as the houses (e.g., Richard's house and Scott's house) in the image. In this case, a viewer who does not know Richard or Scott may be unable to correlate the names with the individuals and to the houses solely on the basis of the metadata that was provided in this example. The user who entered the metadata may be able to provide more specific metadata (e.g., Richard is on the left and Scott is on the right). However, this places a greater burden on the user to enter more information and requires the user to more carefully choose the terms used in the metadata.
In addition, while looking at a digital image taken in years past, it would be beneficial to users who view the image to be reminded or notified who (or what) is depicted in the image and whether or not the object(s) in the image are available for communication. Existing image applications fail to provide this functionality.